Case Study: Reconciling Surface Engineering Data
Survey datasets on oil and gas projects are often inconsistent due to different collection times and contractors for each phase. Drilling, Completions, and Facilities engineers generally re-survey features that may have been surveyed several times already.
In this example on an oil and gas project the locations of the client’s survey and seismic datasets were inconsistent, creating delays and uncertainty for the engineers.
Figure 1: Image of
5 mismatched survey
datasets from an oil
and gas project.
PhotoSat produced a high accuracy 1m topographic survey over the project area from stereo satellite photos. We then determined the relative match between the various datasets and our satellite survey.
Figure 2: Scatterplot of the elevations of the GPS datasets relative to PhotoSat’s satellite topographic survey, showing elevation offsets of GPS2 and GPS3 from the well location. All three GPS datasets and the seismic data are offset 3.5m horizontally from the well survey.
We worked with our client to select a reference dataset and shifted the other datasets to match it. In this case all data was matched to the well site survey. Our unique process resulted in dataset matches to within 10cm vertically and 25cm horizontally, and new, reliable topographic data for future project work.
Figure 3: Scatterplot of the adjusted elevations of the GPS datasets relative to PhotoSat’s satellite topographic survey. These datasets were also adjusted 3.5m horizontally to match the well survey.
PhotoSat also reconciled the offset seismic source points dataset:
Figure 4: Scatterplot of the elevations of the seismic dataset relative to PhotoSat’s satellite topographic survey, showing a 1.0m elevation offset from the well survey. The seismic data is also offset by 3.5m from the well survey.
Figure 4: Scatterplot of the adjusted elevations of the seismic dataset relative to PhotoSat’s satellite topographic survey, matched to the well survey. The seismic locations were also adjusted 3.5m horizontally to match the well survey.
PhotoSat supplied the project team with an adjusted, verified set of survey and seismic data, a matching digital 1m grid of our satellite topography accurate to 20cm in elevation, and a 50cm precision satellite ortho photo accurate to 25cm horizontally.
This reliable topographic data was then used for the subsequent surface engineering design work, reducing project timelines and lowering the costs of ground surface scouting and site surveying.
Figure 6: Colour image
of PhotoSat’s 20cm
accuracy 1m topographic
grid which was used to
verify and adjust the
Figure 7: 50cm contours accurate to 20cm in elevation for the well site for as-built volume calculations and completions and facilities engineering.
Figure 8: 50cm precision satellite ortho photo accurate to 25cm horizontally.